A return mechanism for an operating section such as a switch is required to cause the operating section to surely return to its position. At the same time, the return mechanism is required to cause the operating section to be operable with a smaller force.
Patent Literature 1 discloses a locking piece installation device that applies a force to an operating lever by using a combined spring mechanism constituted by two springs. The combined spring mechanism causes the operating lever to return.
Patent Literature 2 discloses an electromagnetic energy transducer including a magnet, a coil, a movable part, and a spring and configured to convert mechanical energy of the movable part into electrical energy. The spring is connected to the movable part. The spring applies a force to the movable part so as to cause the movable part to return to a predetermined position.
For example, in a power generator in which electrical power is generated by electromagnetic induction caused by displacement of a working section, the faster the working section is displaced, the higher power generation efficiency becomes. In a case where a return mechanism is used to cause the working section to return by itself in such a power generator, it is necessary that the force required for operation be small and that the working section be displaced at a high speed in response to the operation.
Further, in cases other than that of a power generator, it may be necessary that that the force required for operation be small and that the working section be displaced at a high speed in response to the operation.